Automatic regulator for heating apparatus and the like



July 2, 1940. L. HOLLAND-LETZ 2,206,556

AUTOIATIC REGULATOR FOR HEATING APPARATUS AND THE LIKE 'Filed June 14. 1937 4 Sheets-She et 1 July 2, 1940. 1.. HOLLAND-LETZ AUTQIATIC REGULATOR FOR HEATING APPARATUS AND THE LIKE 4 Sheets-Sheet 2 Filed June 14, 1937 L. HOLLAND-LETZ July 2, 1940.

AUTOIATIC REGULATOR FOR HEATING APPARATUS AND THE LIKE 4 Sheets-Sheet 3 Filed June 14. 1937 /8 fZj July 2, 1940- L. HOLLAND-LETZ AUTOIATIC REGULATOR FOR HEATING APPARATUS AND THE LIKE 4 Sheets-Sheet 4 If] VZZ Filed June 14, 1937 f/bZZarzd- 22 Patented July 2, 1940 UNITED STATES AUTOMATIC REGULATOR FOB HEATING APPARATUS AND THE LIKE Ludwig Holland-Lets, Crown Point, Ind.

Application June 14, 1937, Serial No. 148,091

16 Claims.

In the usual types of heating plants for homes, oflices and other buildings, burning hard fuels, the generation of heat is regulated by draft and check damper devices. Where these devices have been controlled automatically, the result has been simply to open or close them, thereby giving only very poor regulation of the fire. Furthermore, in plants where there must be stored up a large amount of heat energy before the thermostat in a room to be heated will be affected, the heat energy thus stored up continues to act after the thermostat has exercised its controlling function, and the temperature of the room rises far above that for which the thermostat is set. A further objection to these old forms of automatic control is that there can be no close regulation of room temperature because of the large gap between the minimum temperature that is reached before an effective inflow of heat occurs, and the maximum temperature when the final surge of stored heat energy is released into the room long after the thermostat has acted; this being particularly true in the case of hot water heating systems where there are large masses of water and metal that are alternately heated and cooled as the fire is increased and lessened.

The object of the present invention is to produce a simple and novel controlling system for overcoming the aforesaid objections and making possible the maintenance of a substantially steady or uniform temperature.

In carrying out my invention, as applied ,to the aforesaid types of heating apparatuses, I provide means for opening and closing the draft and check devices, step by step, so that the draft and check devices may be adjusted as rapidly as is desirable into the most effective positions under any given set of conditions, and be arrested in such positions until the need or desirability of adjustment either in the forward or backward direction arises.

Therefore, viewed in one of its aspects, the present invention may be said to have for its object to produce a simple and novel thermostatic control, not only of heating plants, but in other situations where it is desirable that there be a flexibility of control determined by a temperature "condition; as, for example, for the purpose of regulating steam supply lines for heating or oven purposes, for varying the speed of automatic stokers, and for many other heating uses.

The various features of'novelt-y whereby my invention is characterized will hereinafter be pointed out with particularity in the claims; but, v

for a full understanding of my invention and of its objects and advantages, reference may be had. to the following detailed description taken in connection with the accompanying drawings,

wherein:

Figure l is a more or less diagrammatic view 5 of a system embodying the present invention; Fig. 2 is an end or side view of the mechanical elements illustrated in Fig. 1; Fig. 3 is a view, on an enlarged scale, showing, partly in elevation and partly in section a fragment of the thermostat, together with the contact terminals associated therewith and controlling means for said contact terminals; Fig. 4 is a top plan view of the parts shown in Fig. 3; Fig. 5 is a section on a still larger scale on lines 5-5 of Fig. 3; Fig. 6 is a section on line 8--6 of Fig. 3; Fig. 7 is a diagram illustrating the application of the mechanism illustrated in Figs. 1 to 6 applied to a boiler or furnace having draft and check damper devices; Fig. 8 is a View similar to Fig. 7, with the boiler 20 or furnace omitted, illustrating a system in which there are no mechanical connections between the thermostatic devices and the parts to be controlled thereby; Figs. 9 and 10 are vertical sections through a thermostatic device of the type employed in the system illustrated in Fig. 8, these sections being taken respectively on lines 9- -9 and i0i0 of Fig, 11; Fig. 11 is a front view of an electro-magnetic controlling means for the contact terminals cooperating with the thermal element of the thermostat in the system illustrated in Fig. 8; Fig. 12 is a side or edge view of the parts shown in Fig. 11, with the addition of a cover or housing shown in section; Fig. 13 is a frontyiew of mechanism to be applied to the immediate draft and check damper operating devices in Fig. 1 where the contact terminals cooperating with the temperature sensitive element are to be controlled electro- -magnetically, as in Figs. 9 to 12; and Fig. 14 is a side or end view of the parts shown in Fig. 13, together with associated elements and parts of a wiring diagram.

Referring to Fig. 7 of the drawings, l represents a rocker beam fixed at the middle to a supporting shaft 2 and having its ends connected Ell which the thermal element is mounted.

through speed reduction searing. Thus, roe tor shaft hes thereon a pinion :3 that meshes with a large gear wheel ll] on a shaft 5!! parallel with the shalt 2. The M has a golrllou l2 meshing with a large gear segmeut l fixed to the shaft 2. Gwreut supplied to the motor through. the secondary of a transformer thromh a reversing switch 66. that the reversing swlt/ch has three positions, forward, reverse and ueutrel, it will be J by properly shifting the swltch, the rocker beam may be swung be either dlrectloh desired angle and be brought rest llmlt of such movement.

The swltch'ls controlled by a thermostatic device containing any usual or suitable tempera= ture responsive member whi h, lrl arrange= meet shovm, ls a blmetcl s" anchored cue end and having long free a ll thet swings back and forth as its temperatlue increases decreases. The thermal elemeut ls sl'iovm being grounded at one end, ls also one tcr=- ellgued screws 9 and 21); these screws b21315;

a sudtable body 23 cl insulating me. erlal ar ranged between the upper ends or and carried by e. pair of spring metal strips 22, 22 that lie on opposite sides of and approximately parallel with the arm ill. The lower ends of the elements are secured to the same base or blccl; upon The extreme upper ends of the arms or strlps .22 are connected together by a cross piece integral with the same and forming therewith an inverted U- shaped frame anchored at its lower end. The upper end of this frame, carrying the contact screws 59 and 2d, may be deflected to the right or to the left, returning when released, to its normal uprlght posltiou. In this way the contact screws 59 and 2d may be shifted bodily to the right or left without coming out of line with the contacts 08 on the member 6?. On top of the U frame is fixed a metal strip 25 which extends laterally beyond one side of the U frame and is there curved downwardly and inwardly to form a rounded projection 26. The screws [1%) and 220 form, with the contacts 08, a double-throw swltch of which the members 68 form the movable contacts and in which the screws are also movable, not only to effect an initial adjustment of the gap when the switch is opera, but in order, under Fill out of alignment with the contact pieces d.

In the particular arrangement illustrated, this shifting of what may be termed the supporting frame for the terminal screws is caused by the turning of the shaft 2. It will be seen that there is supported beside the thermostatic device a vertically-slidable round rod El; this rod extend lng through a stationary bearing block 28. The rod has in the upper end a deep slot 29 opening out through the side andthrough the top. Within this slot is positioned a short rectangular bar fill projecting out through the slot and through the side or the bearing block 2&3. The outer edge of the member SE) is inclined so that when the lo er part thereof engages the projection or lug 26, the upper part of the edge overhangs the same. Consequently, the rod is pulled down, it will push the projection and therefore, the upper end ol the supporting frame for the screws 123 and toward the right, as vlewed in Fig. 3. When the rod is pushed up again, the resiliency of the arms or strlpsdd causes the frame to be returued to lts lnltlel position. The part Bl] is secured to the rod by a hinge pin 3i at its lower and, extending through the bottom wall of the slot 29 behind the i ember 33 is a headless screw 32, the position of whlch determines the lucllnetlon of the outer or working edge of the member upper end of the member 538 may be sharpened to a polut as indicated at 36 for cooperatlou with a graduated scale 3?.

lower end of the rod ill is made tubular, ludicated at This tubular part is telescoped upon a stationary tubular element 3'2! which extends down lute the vicinity of the shaft i ilthlu the upper part of the tubular member Ell end the tubular part is a compresslori spring that ends constantly to hold rod with lts wedge member raised. The may be drawn down by a wire or other sui able m mber extending up through the tubular members 53? and 36 and having its upper end anchored to the rod 2?], as for example, by a set screw ll]. The lower end of this wire is attached to a strap one end or which is fastened to a hub-like portion 62 or enlargement on the shaft With this construction, when the shaft 52 is turned in one direction, it winds the strap upon the hub :32 and thus pulls down the rod 27 with its wedge device. When the shaft stops, so does the movement of the rod. When the shaft turns in the opposite direction, the strap unwlnds and the spring 38 ls free to move the rod up far enough to talre up the slack in the wire and strap.

As will hereinafter be explained, the switch device just descrlbed controls the operation of the motor, causing it to start in either direction and stop in a manner to provide an approximately uniform temperature in the room or space where the thermostat is located, after a suldciently hot fire has once been established. The motor is controlled in two ways: first, to produce a step by step regulation of the draft and check devices; and second, to determine the direction in which the motor ls to turn. The step by step operation of the draft and checl: devices insures a gradual variation in chhuuey pull on the fire, but only when and as warranted by the rise in temperature, and the maintenance of the effective chimney draft at any desired stage which is best suited to maintain the desired temperature after that temperature has been reached. The

controlling of the motor for forward or reverse operation not only permits the check damper to be fully closed and the draft to be opened wide whenever occasion demands, but it enables the controlling apparatus to speed up the fire again. after having partially closed the draft or partially opened the check damper. In other words, not only are the closing" of the draft and the opening of the check damper effected step by step, but a status quo may be established anywhere within the range of movements of these devices, and they may at any time begin to move backwards step by step, when conditions demend it.

Tue two energizing circuits for the reversing switch actuating means pass through a limit switch which causes the opening of either cir cuit which happens tobe in use whenever the shaft 2 has been turned to one or the other limit of its angular movement. This switch comprises a stationary block of insulating material 44 having thereon two stationary contact pieces 45 and 46 of elongated or oval shape, together with an arm 41 loosely hung on the shaft 2 and carrying contacts 48 and 48 which have sliding engagement, respectively, with the stationary contact pieces 45 and 46. The swinging member 41 has at its lower end a lug 50 that lies between the upper ends of a pair of spring fingers 5| anchored at their free ends to any suitable support. Between the spring fingers, toward their free ends, but clear of the lug 50, is a stationary pin 52 against both of which the spring fingers are pressed when free to do so. The parts are so proportioned that normally the spring fingers both touch the post, holding the swinging member 41 in such position that the contacts 45 and 48 engage with each other and the contact 4Q engages with the contact 46.

On the gear segment M are two lugs 54 and 55, spaced apart a distance corresponding to the angular distance through which the gear segment and its shaft 2 are adapted to turn; the lugs being on the side toward the swinging contact carrier 41 and projecting into the plane of the latter. When the gear segment I4 approaches one limit of its movement, one of the lugs engages with the swinging member 41 and carries it along until one of the contact pieces 48 and 49 rides beyond the stationary contact with which it cooperates; while, when the gear segment approaches the other limit of its movement, the other lug engages with the member 41 and swings it in the opposite direction, causing the other of the two movable contacts 48 and 49 to leave its cooperating stationary contact. As will hereinafter be seen, the circuits are; such that the one that happens to be holding the reversing switch for the motor closed, at the time the gear segment reaches either limit of its movement, is interrupted at the limit switch just described. When this occurs, the shaft is at one extreme limit of its oscillating movement and cannot be started again except to run in the opposite direction from that in which it was running when brought to a stop. When the motor stops, the gear segment is, in effect, held against turning backward, so that the spring finger 5| that has been pushed away from the post 52 cannot return the member 41 to its normal intermediate position, because this member is resting against that lug 54 or 55 that has just moved it out of the intermediate position. Consequently, the limit switch remains in the position that permits the motor to be started again, but only in the reverse direction from that which caused the limit switch to open.

The reversing motor switch I6 is actuated by two pairs of electro-magnets 56 and 51. The movable member of the switch is fixed on one end of a rocking armature 58 underlying the electromagnets and pivotally supported, as at 59, at the middle thereof. When one pair of electro-magnets is energized, it acts on the armature to swing the switch into the forward position, while the energization of the other pair of electro-magnets causes the armature to be operated in the direction to place the switch in reverse. When all of the .elec'tro-magnets are deenergized, the switch should be in its open position which, in the arrangement shown, is midway between forward and reverse. For the purpose of holding the motor switch open when the ele'ctro-magnets are all deenergized, I provide the armature 58, on the end opposite that at which the movable part of the motor switch is mounted, with a grooved roller 60 against which bears a rod 5| hinged at its upper end to a stationary support, as at 62; having therein a V-shaped bend 64 so placed that one'side or the other of the V contacts with the roller 60 in either working position of the switch; the lower or free end of the rod 6| being anchored to a stationary support through the medium of a tension spring 65. The spring 65 is powerful enough to cause the sides of the V in the rod 6| to force the roller into the lowest point of the V when the magnets are deenergized.

Means are provided to hold the switch in either of its two working positions, after having been brought there, until the motor has completed a predetermined number of revolutions. In the arrangement shown, the number of revolutions that the motor makes before stopping, after having once been started, is such that the shaft H is turned through half a revolution. This is accomplished by fixing on the shaft i underneath the motor switch operating electro-magnets, a disk 66 having at diametrically opposed points thereon pairs of lugs 61 and 68, projecting laterally from both sides thereof. Iil'iese lugs are triangula;- in cross section, one apex or ridge of each lug being fiush with the periphery of the disk. On the under side of the armature 58 is arranged a swinging dog 69, the free end of which lies between and is pinned to ears It on the armature, thereby permitting vertical swinging movements of the dog. The armature is provided with additional lugs 15 lying on opposite sides of the dog near the free end of the latter so as to prevent the dog from swinging or twisting sidewise. The dog lies just below the pivotal axis of the armature, so that it swings with the armature through a small angle from one side to the other of a vertical plane containing the pivotal axis of the armature. The dog 69 has on the under side, near the free end, a V-shaped nose 12, and it may also be provided with a pin 14 extending through the same and projecting on opposite sides thereof just above the nose. The disk 66 lies in the vertical plane containing the pivotal axis of the armature, which is also the plane of the dog 69 when the switch is in its neutral position. The parts are so proportioned that the nose of the dog may either rest on the edge of the disk 66 or lie on one side or the other thereof, with one end of the projecting pin 14 resting on the disk edge.

with the partsin the positions illustrated in Fig. l, with the nose of the dog on the righthand side of the disk 66, the motor switch will remain in the position illustrated, even though the electro-magnets 51 have been deenergized, because the dog 69 acts as a lock bearing against the disk 66 and preventing the switch opening device consisting of the bent rod GI and the spring 65 from swinging the switch into its open position. However, assuming that the disk 66 is turning in the counter-clockwise direction in Fig. 2, when the nose 12 on the dog reaches the lug 61' on the corresponding side of the disk, it rides up on one of the inclined faces of the lug until it rises to the extreme periphery of the disk. As soon as this occurs, the spring actuated switch opener comes into play, forcing the roller 60 on the armature 58 into the angle of the V in the rod BI and opening the switch and simultaneously shifting the dog lit into a .vertical position in which it rests on the edge of the dish ready to be swung to either side of the dish, depending upon whether the magnets or ill are the next to be energised.

The dog to serves an additional purpose. \On top of the motor switch operating device is a switch comprising a spring arm lb anchored at one end lying above a spring arm llG, also an=- chorecl at one end. The member 716 is connected to the dog til by a suitable linl: or strut Hi. The parts are so proportioned that when the nose of the dog is resting on the periphery of the dlslr, the switch arm it is pressed up against the arm l5 which is caused to be deflected upwardly somewhat; the switch being closed and its two members serving as springs under tension adapted to throw the dog down and simultaneously open the circuit whenever the dog is oscillated to carry its nose to one side or the other of the disk 6b. In this way the energizing circuits for the actuating magnets 56 and Eli are completed so far as the switch l5, W8 is concerned, whenever the motor stops, it remaining only for the contact it; to engage either oi the terminal screws 09 and 2t], in order to start the motor in forward or reverse, as the case may be.

The operation of the system just described will now be explained. It may be assumed that in the drawings the motor is just about to stop with the draft fully open and the check damper fully closed, the dish needing to turn only through a small angle in the counter-clockwise direction, in order to lift the nose of the dog 69 level with the periphery of the dish and permit the spring actuated motor switch opener to throw the motor switch into its neutral position. As soon as the motor switch opens, everything remains at a standstill until the temperature oi the atmosphere by which the thermostat is in= fiuenced rises sufllciently to cause it to talse control. If it be that there is no fire in the furnace and a fire is started, nothing will happen until the temperature of the room in which the thermostat is located comes somewhere near the desired maximum temperature. Then the thermal element I7 swings a little toward the right, as viewed in Fig. 3, closing the gap between its contact piece l8 and the terminal screw it. Perhaps it should have heretofore been stated that the distance between the inner ends of the terminal screws is only a few thousandths of an inch greater than the overall thickness of the thermal element in the region of its contact piece It, so that contact can be made with only one of the terminal screws at a time. With the room cold, contact is with the lefthand terminal screw 59 in Fig. 3. As shown by the diagram in Fig. l, the terminal screw it] is connected to the contact 46 of the limit switch through a wire 18. However, this contact is out oi engagement with its cooperating contact 39, and therefore, no current can flow through any circuit which might otherwise have been established through the thermostat device. However, after the lire has developed sufiiciently to cause the thermal ele ment to swing to the right in Fig. i and make contact with the terminal screw it, a circuit is completed from ground through the thermal element l7, through the terminal contact screw 20, the wire '19, the contacts 65 and M5 of the limit switch, wire 80, coils of the electromagnets 56, wire 8|, switch members it and i6, and wire 82 to one terminal of the transformer secondary I5. The other terminal of the transformer being grounded, the circuit tor the accepts eiectro-magnets B3 is completed and the armsture so, which was occupying its neutral tion, is drawn up by the electro-magnets 56. Thus, the motor switch is closed in a manner to cause the motor to operate in the direction" to turn the gear segment i (1 in the counter-elude wise direction, and the dish in the clockwise direction, as viewed in As soon as the dish 66 has traveled far enough to permit the nose of the dog to drop down beside the dish, as shown in Fig. 2, the armature is locked to hold the motor switch closed, but the circuit through the electro=magnets is interrupted at the switch members 15 and 716. This interruption of the circuit is important because it a continuous flow of current through the temperature responsive member oi the thermostat were permitted, it would become heated by the current and no longer be accurately'responsive to the tempera= ture of the surrounding atmosphere. mining the running of motor the shait is being turned so as to rock the mam K through a small angle and begin winding the strap 5t upon the hub When the chair has completeda halt-turn, one of lugs 68 engages with the nose E2 on the dog, lifting the dog and causing the motor switch to he opened. By the time that the motor switch has been opened and the motor stopped, the lug on the gear segment M has moved far enough away from the swinging member of the limit switch to permit this member to be brought into its central or neutral position in which each of the movable contact pieces to and til engages with its cooperating stationary contact piece. strap'on the hub of shaft 2 causes the sliding rod 2*] to be drawn down and the wedge member 30 to force the upper end of the carrier for the terminal screw contact pieces l9 and it toward the right, as viewed in Figs. 1 and 3, thereby again openlnga gap between terminal screw 20 and the corresponding contact l8; Nothing further happens until this newly created gap has been closed, whereupon the cycle just described will be repeated and the rocker beam i will be turned a little farther in the direction that will cause the draft to be reduced. This cycle may be repeated as many times as is desired. For example, there may be as many as a dozen steps or stages in moving the gear segment on the shaft 2 from one limit to the other. Various eifects may, of course, be obtained throughout the course or" such a series of steps or stages. I! desired, the first six steps or stages could be employed progressively to shut oh the draft. Then, the last six steps or stages could be employed gradually to open the check damper.

It will be seen that whenever the thermal element of the thermostat falls to move far enough ahead to prevent the closing of the gap between.

the same and the trailing terminal screw, the rotation of the motor will be reversed because, except when the gear segment is at either limit of its movement, the limit switch is closed, and therefore, whenever the thermal element it makes contact with the screw iii, the circuit is completed through the limit switch members 46 and 49, through the wire 84 to the coils of the electromagnet 51 and from there through the wire 8!, switch members 15 and I6, and wire 82 to the secondary of the transformer. If the relative shifting movements of the terminal screw contacts and the thermal element H for any stage or step are such that the circuit is interrupted at both terminal screws, the shifting of The winding oi the the draft device or check damper,or both, de-

pending upon the manner in which the multiple stages or steps are employed, ceases until contact is again established with one or the other of the terminal contact screws.

With my improved system, very close temperature regulation can be obtained, something which is impossible where the draft and check devices are simply closed or opened to their full extent as determined by their adjustment in any particular installation; the control of the fire beginning at any convenient room temperature below the maximum temperature desired, and thereby preventing the accumulation, in the heating system, of an excessive amount of heat energy which will be delivered into the room after the maximum temperature has been reached and thereby cause the room to become much hotter than is desired. Not only are unduly high temperatures avoided, but as long as the fire is in condition to permit a sufilcient fiow of air therethrough, there need be no excessive drop in room temperature. Should the temperature drop more than a few degrees, it is evidence that the grate needs shaking or that the fuel should be replenished; and, when the deficiency in this respect is remedied, the automatic control is resumed without further care or effort on the part of the user. Always; when necessary, the full range of the draft and check devices may be utilized and they are not restricted to alternate complete closures and partial openings as is the case where the draft and check devices must initially be adjusted to utilize less than, and perhaps only a small fraction of, the whole range of control that would otherwise be afforded.

The spread between minimum and maximum room temperatures to enable the full range of draft and check control to be carried out varies greatly with different kinds of fuels and different types of heating systems. As already stated, in some systems there is so much water and metal that must be heated, that the temperature in a room may rise a good many degrees above the desired maximum if the regulation is performed in the ordinary way. By employing the adjustable wedge device with the graduated scale, I make it possible to vary the spread between the minimum temperature at which control of the fire begins and the maximum temperature desired. By adjusting the wedge device, the transition from a condition of full draft, throughout the entire series of steps or stages, to a condition of full check, may be carried out while the room temperature varies only two or three degrees if the conditions are such that room tem perature responds very quickly to changes in the condition of the fire. On the other hand, the low temperature at which regulation is to begin may be eight or ten degrees below the desired maximum, so that the room temperature may rise as much as ten degrees while the entire series of steps or stages are carried out through the com-. plete draft and damper range.

Where the thermostatic controller is not far from the shaft carrying the rocker beam, the means just described for synchronizing the movements of the rocker beam with movements of the screw contact terminals in the thermostatic device is satisfactory, but if the distance be great or it be necessary for the wire 39 to turn corners, it may be advisable to employ electrical instead of mechanical means for bringing about this synchronization. I have illustrated such means in Figs. 8 to 14. The system as a whole requires no change, but only the means for moving the frame that carries the contact terminal screws. Thus, for example, the frame that carries the terminal contact screws l9 and 20 in the temperature responsive switch may have an upwardly extending finger instead of the lateral projection 26 in the form previously described. This finger may engage with any suitable actuator therefor. In the arrangement shown, the engagement is with a face cam 86 fixed on one end of a rotatable shaft 81 mounted above the switch device. This shaft is shown as having fixed thereon two toothed actuating wheels 88 and 89 and a toothed locking wheel 90 positioned between the other two. Each of the wheels 88 and 89 has as many similar teeth as there are steps or stages of control, together with a broad tooth 9|. The wheel 90 is provided with a radially projecting stop pin 92. Above each of the wheels 88 and 89 is an electro-magnet, these being indicated at 94 and 95 respectively. Below each electro-magnet is a vertically swinging armature 96 provided with a plunger 91 extending up into the interior of the corresponding coil. Hung from the lower ends of the armature plungers or cores are links in the form of narrow, fiat plates 98 and 99, respectively. As best shown in Fig. 9, each link has therein an oblong hole or cam slot I00 through which the shaft 81 passes. These cam slots are oppositely disposed so that when one armature is drawn up upon the energization of the overlying coil, the corresponding link is raised and, at the same time, swung upwardly; while upon the energization of the other coil, the other link is raised and swung forwardly. These movements of the links permit laterally projecting pins llll on the lower ends thereof to engage the teeth on the adjacent wheel 88 or 89, as the case may be and cause the shaft 81 to be turned, in one direction or the other, through steps equal to the angular length of a tooth. There is a tension spring I02 between the pin ill! on the link 98 and the corresponding armature which swings the link forward far enough, upon the lowering of the link, to place the pin in position to engage the next tooth when the armature is again energized. The link 99 is similar to the link 98, but because the cam slot in the same is oppositely disposed relatively to the slot I02, this link drives the shaft 81 in the opposite direction from the turning movements caused by the link Q8. The link 99 has associated therewith a spring HM that swings the link rearwardly past center when the armature drops and brings the pin on the link into position to take a new hold on the toothed wheel 88 when the armature is again raised.

Whenever the shaft 8'! is turned until the pin on the active link or driving pawl reaches the wide tooth 91 on the toothed wheel with which it cooperates, the shaft has reached one limit of its oscillatory movement; for, if the same electromagnet which has been driving it is again energized, the pawl associated therewith simply rides on top of the wide tooth and takes no hold on the toothed wheel. It will be seen that this arrangement insures that if one of the pawls should jump over one of the teeth of the corresponding wheel and thus bring the shaft 81 out of synchronism with the draft and check devices, correction will automatically be made and proper timing be re-established when the shaft is again ooemlor ocsitiori mto which it may he turned. When the sheit is rotated in one direction, the pin eventually strikes against the free end of the detent, thereby preventing any further ro= tetioii in. thet direction. When the she-it is ro= teted in the opposite direction, e condition is finally crested in which the pin strikes eeeiost o ree-rwerdly facing shoulder 6016 on the under side of the detent. This prevents iurther rota,- tion of the shaft in that direction.

As the shaft 8? turns step by step, the face com to is also turned in the some meririer end, therefore, progressively presses the finger to-= werd the left, as viewed in ii, or permits the resiliency of the members to carry the finger toward the right as the com face recedes,

depending upon the direction in which. the shsft i is rotated. it will thus be seen that the electro-megriets 96 end. ere energized at the proper times, the teminel screw contacts 69 end Eli are moved sidewise step by step, in the some creamer its is done through the QiGZiODl oi the wedge device in the first form of the invention.

in Figs. l3 and it there is illustreted as simple arrangement for controlling the eriergizetiom oi the electroonogrrets 96 end Near the shaft M and in the vicinity of the dish to is locsted 9. fixed contest loll. Between this iizzed coritect acid the dish is 9. spring arm nos anchored et one end, es indicated at it?) and having at its free cool e. contact are in position to he engaged with 1 the contest Mil. Normally, the resiliency oi? the spring errc lilo holds the contact till away from. the contact lt l. The spring erm tilt! has there on, opposite dish. E56, o projecting log t l l hov hie sloping feces meeting in s. ridge. @ne of each pair of lines or projections on disls that serve to roles the dog 69 is elongated, es indicsted at tie and title,- in order extend. across the arm tilt-l. The parts ere so proportioned that midway in each heli revolution of the dist. 6, one of these elongated lugs engages with the log till end rises the contact Mo to he engaged with the cont .o. Mill.

Also, on the shaft 2 is a loose dish M23 having thereon o. rsdlel erm Md carrying on its outer mil 8. contact piece lit. The free end of the arm il l lies between two stationery contests H6 and ill spread apart a. distance somewhat greater than the thickness of the contact its, whereby the letter engage with either 01? the first two contacts, but not with both at the some time. Suitable means for irictionslly holding the mem her 2 against turning movements relatively to the shaft 2 are provided, whereby, whenever the shaft turns, the member M2 turns with it until arrested through engagement of its contact with one of the stationary contacts Mil end til. Thereafter, while the shaft continues to turn in the same direction, there is no further movement of the member H2. But, when the shoft 22 begins to turn in the opposite direction, the member H2 is carried along with it through the limited angle necessary to carry the contact M away from the stationary contact with which it was engaged and against the other of the twocooperating stationary contests. I

The wiring in Figs. ii and it includes two wires H8, H9 which may be assumed to be con-- nected to the terminals of the secondary of the transformer; the wire H8 being grounded, and the wire 9 being connected to the contoct no. The stationary contact I01 is connected to the contact lli by a. wire i213. Stationery contact H8 is connected by a. wire iii to one terminal citing circuit for the electro=rl of the electro mecoet 534 the other terminal of moi of the coil of the electro=meeiiet 96 through c. wire the other terminal oi this coil hegrounded through the wire S22. thus he seen thet whee the motor ci closed so as to cause the shaft 2 to too direction. scythe co-iiritcr=cloclswise dile viewed in Fig. 14, one of the two switches in 9G is closed while the other (contacts MG 1:. However, otter the dish 66 has turn, one oi the lone :roiectiocs on the gages win the projection ill on the s tch arm egeiost contact referr .i to is closed-end the electro mermet to A the dish continues to the end half tum, the switch arm 0638 is released and settings heel: to its normal position, openmg the circuit for the electro meeriet 9d. Flosever, this circuit has remained closed long enough for the cowl ratchet mechanism ectueted by this electro-megnet to turn the shaft (it through one step. As long 2.5 the circuit to the moto continues to he completed in e manner to cause the motor to turn in the some direction, the electrmmogriet so is energized once during each cycle of the motor. As soon es the motor is ceased to term the opposite direction.

the member M2 on the sheit i2 is shifted so as to move its contact Elli away from the contact lite-moi into engagement with the contact ill. Now, whenever the contact MG meets the con.- tect itll, the energizing circuit for the coil of the electro-msgriet so is completed, end the turning movements of the shaft eretheri reverse of what they were before.

In the arrangement illustrsted, the dish-like member 9 i2 beers at one side egsinst o coller U24 fixed on the shoft 2, while o. irlctiorl dish or shoe llli engages with the opposite side or face, Between the friction slice B25 and e. caller tiltedjustohle elong the shaft 2, is e. comzsressiori spring i211 which causes the port M2 to he yieldingly clemoed between the collar i2 3 and the shoe 825.

it will thus be seen that I hove provided simple and reliable means for moving as controlling memher for a. heater or other apparatus, mechanism, or device step by step, heclrwerd and forward, in sensitive response to rise end fell in the temperature of the master controller; end that while the movement of seid controlling member may proceed step by step from. one limit to the other, the

desired. Furthermore, while I have not filUS-.

trated any means for varying the temperature rouge through which the electrically-controlled master switch may be efiective, it is obvious that provision for such adjustment may easily be made. Thus, for example, by employing interchangeable cams in which the slopes of the working faces are steeper or less steep than that of the cam illustrated in Figs. 11 and 12, the same effect may be obtained as through the changing of the inthe errerclination of the wedge member 30 in the form illustrated in Fig. 1. Another way of accomplishing the same end is to substitute a pinion for the cam on the shaft 81 and engage it with rack teeth on the bar 21 in the form of controller shown in Figs. 1 to 4.

Therefore, while I have illustrated and described in detail only a single preferred form of my invention, together with a single modification in the operating means for the control of the temperature-responsive switch, I do not desire to be limited to the exact structural details thus illustrated and described; but intend to cover all forms and arrangements which come within the definitions of my invention constituting the appended claims.

I claim:

1. In combination, heat regulating means, an intermittently operated power unit for operating said heat regulating means, a temperature sensitive member having oppositely disposed electrical contacts, a pair of spaced electrical contacts carried by a movable member so as to confront said first named electrical contacts, means on said power unit for imparting movement to said movable member and its confronting contacts relative to said first named electrical contacts, an electromagnet for starting said power unit, a rocking armature for said electro-magnet, a dog movably carried by said armature, a disc having lugs thereon rotatable by said power unit in the path of said' dog, said dog riding said disc and normally disposed in the path of said lugs, electric circuit breaking means in the path of said dog to make the circuit for said electro-magnet when contacted by a lug on said disc and break the circuit when the dog drops intermediate said disc lugs to cut the temperature sensitive member from said circuit, a three-way'electric switch actuated by said electro-magnet for energizing, de-energizing and reversing said power unit and operable responsive to said temperature sensitive member and movable member connected in the circuit therewith, electrical connections between said temperature sensitive member and opposing movable terminal member and said electro-magnet including said three-way switch, limit switches in said circuit for controlling the range of movement of said heat regulating means and the position of said movable member.

2. The combination with a heating system, of regulating means including intermittently operated power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, switching means for starting and stopping said power means operating in either direction, locking means to insure operation of said power means through one of said equally divided stepped positions of said predetermined limits, and means sensitive to temperature changes for initiating said switching means to start said power means and said regulating means for each of said equal divisions of step movement.

3. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, mechanism actuated for starting and stopping said power means operating in either direction through one of said equally divided stepped positions of said predetermined limits, an electric circuit, means sensitive to temperature changes in said electric circuit for initiating said mechanism to start operating said power means and said regulating means for each of said equal divisions of step movement, and means operated by said power means for removing said temperature sensitive means from said circuit after each of said predetermined equal divisions of step movement's has been initiated.

4. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, mechanism actuated for starting and stopping said power means operating in either direction through one of said equally divided stepped positions of said predetermined limits, an electric circuit, means sensitive to temperature changes in said electric circuit for initiating said mechanism in starting said power means and said regulating means for each equal division of step movement, means operated by said power means for removing said temperature sensitive means from said electric circuit after each of said predetermined equal division of step movement have been initiated, and means for holding said mechanism locked in position while each of said divisions of step movement is in progress, means for unlocking said mechanism each time said equal stepdivision has been completed.

5. The combination with a heating system, of regulating means including intermittently operated power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, switching means for starting and stopping said power means operating in either direction, locking means to insure operation of said power means through one of said equally divided stepped positions of said predetermined limits, a circuit contact member, an electric circuit, means sensitive to temperature changes in said electriccircuit and having movement to cooperate with said circuit contact member for initiating said switching means to start said power means and said regulating means for each of said equal divisions of stepped movement, and means operated by said power means for separating said circuit contact member and said temperature sensitive means during each of said equal step divisions of movement.

6. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, switching means for starting and stopping said power means for operating in either direction, locking means to insure operation of said power means through one of said equally divided stepped positions of said predetermined limits, an electric circuit. a circuit contact member, means sensitive to temperature changes in said electric circuit and having movement to co-operate with said circuit contact member, means sensitive to temperature changes for initiating said switching means to start said power means and said regulating means for each of said equal divisions of step movement, means operated by aid power means for separating iii) till

number of a series of equally divided stepped positions, mechanism actuated for starting and stopping sold power means for operating in either direction through one of sold e uslly di vlolecl stepped positions or sold predetermined limits, on electric circuit, s circu t contact ruero= oer, means sensitive to temperature changes in said electric circuit end having movement to eo=- operate with sold circuit contest member, s flexilsle pull connecting" means between sold circuit Contact member and said power means for mov said contest member in ouedirectiori, and means for keeping sold flexible pull connection tensioned for moving said circuit corite-ctmeoos the opposite direction, said flexible means Toepulled by sold power mesus tor seporetirig said circuit contact member and said temperature sensitive means during each of sold e usl divisions of stepped movement, said tempereture sensitive meorisservlne to start said power means end sold regulating means tor each of sold eouel divisions oi stepped movement.

8. The combinetiori with o liestlrle system, of regulating means including power WEEDS end a heat control member adopted to be moved back and forth by said power means between credo terminecl limits constituting e predetermined number of a series of equally divided stepped positions. mechanism actuated for starting and stopping said power means operating in either direction through one of sold equally divided stepp d positions of sold predetermined limits, s. lease member, s temperature sensitive means supported by sold loose member, s substantially U-slzeperl flexible swinging frame member loaving the cost: end of U-p-arollel orms secured to said hose member, s coir of opposing contacts cooperating with said temperature sensitive means, listed to the closed end or" sold U- shepeol frame member, and means operated by said "power means "for flexible sold U-shepecl frame member to separate contact with said temperature sensitive means during each of said equal divisions of stepped movement, the re= spouse of sold temperature sensitive meons serving to initiate sold mechanism to start said power means and said regulating means for each of ceidequel divisions of stepped movement.

9. The combination with e heating system, of

regulating-means including power means and a,

heat control member adapted to be moved back and forth by said power means between predetermined limits constituting e predetermined number of a series of equally divided stepped. positions, mechanism comprising a pair of opposed electro-rnognets, and armature, said electro-megnets cooperating with said armature, a three way switch, said armature operating said three way switch, a rotatable indexing cam haw ing a neutral position interposed by two positions for operating said armature and said ,three way switch in reverse direction for starting and stopping said power means for operating in either o oi equally divided stepped color or sold. predetermined limits, a two way switch. in our electric circuit, moons sensitive to temperature in said circuit, means octueteol lo sold emmoture for closing said two way switl 1 m the neutral position of said indexing e circuit contact member, said temperature sensitive means having movement to ccoperete with said crlcuit contact member for initiating sold mechanism to start said power memos voriol sold regulating means for each of sold e uol divisions of stepped movements, and means operotecl for said power means for importins; movement to separate contact of said contract member and sold temperature sensitive mesiis each or equal divisions of movement.

lit, Tire combination with as heating system, of reguletiris including power means end a lieet control member selected to be moved heel: and forth "my cold power means between predered limits constituting a predetermined number of series of eousllv divided stepped positions, rreeiierilsm actuated for starting and stopping said power meters operating in either direction through one of sold equally divided stepped positions or sold predetermined lire its, on electric circuit, e, circuit contact mem= loer, rrieeus sensitive to temperature changes in directiorr so said electric circuit and having movement to cooperate with solid circuit contact member, s. uniform reversing step'lov step motor comprising c, pair of electro meerlets provided with arresttures, ratchet growls carried by said ormatures, rotstelily jourrielled ratchet wheels, one or said oowls having ratchet engagement to rotate one or said ratchet wheels in one direction and the other ratchet pawl leaving ratchet wheel engagement for rotating the other ratchet wheel in the opposite direction, on electrical current distributor operoted or sold power means, said distributor moving o irlctlonslly held directional contact seiectirigmemloer for selecting either of said electro-moeriets to ice energized with an electrical impulse during sold equal divisions of movement. and means octueted by sold ratchet wheels to cause movement to separate contact of said circult contact member and said temperature sensitlve means during each of sold equal divisions of stepped movement the response of said temperature sensitive meoris serving to initiate said mechanism to start said power means and said regulator means for each of sold equal divisions of stepped movements.

ll. The combination with a heating system, of regulating means including power means and a heat control member adopted to be moved back and forth by sold power means between predetermirieol limits constituting at predetermined number of or series oi equally divided stepped positions, mechsuism actuated for starting and stopping sold power means operating in either direction through one of said equally divided stepped positions of sold predetermined limits, on electric circuit, a circuit contact member, means sensitive to temperature changes in said electric circuit and having movement to cooperate with said circuit contact member, an electrical uniform step by step motor, an eleccircuit contact member and said temperature sensitive means, and travel limit stop means for limiting the travel of said step motor in both directions to conform with the said predetermined number of' said series of equally divided step positions, the response of said temperature sensitive means serving to initiate said mechaism to start said power means and said regulating means for each of said equal divisions of stepped movements.

12. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, mechanism actuated for starting and stopping said power means operating in either direction through one ofsaid equally divided stepped positions of said predetermined limits, an electrical circuit, a circuit contact member. means sensitive to temperature changes in said electrical circuit and having movement to cooperate with said circuit contact member, an electrical uniform step by step motor, a pair of opposed contacts, an electrical current distributor operated by said power means, said distributor having a contact selector for selecting either of the said opposed contacts to determine the direction in which said step motor shall operate, means for limiting the current distributor circuit to a short impulse constituting only a fraction of the duration of said equal division of step movement, and camming means operated by said step motor for imparting movement in either direction to separate contact of said circuit contact member and said temperature sensitive member means, the thermal response of said temperature sensitive means serving to initiate said mechanism to start said power means and said regulating means for each of said equal divisions of stepped movements.

13. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back to start said power means and said regulating means for each of said equal divisionsof stepped movements.

14. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth bysaid powermeans betweenprede-.

termined limits constituting a nmnberofaseriesofequallydividedstepped,

positions, a switch control mechanism for starting and stopping said power means for operating in either direction through one of said equally divided stepped positions of said predetermined limits, means for holding said mechanism locked in position while said equal division of step movement is in progress, means for unlocking said mechanism each time said equal step division has been completed, means sensitive to temperature changes for initiating said mechanism to start said power means and said regulating means for each of said equal divisions of stepped movements.

15. The combination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth by saidpower means between predetermined limits constituting a predetermined number of a series oil-equally divided stepped positions, a switchcontrol mechanism for starting and stopping said power means for operating in either direction through one of said equally divided stepped positions of said predetermined limits, means for holding said mechanism locked in position while said equal division of step movement is in progress, means for unlocking said mechanism each time said equal step division has been completed, means sensitive to temperature changes for initiating said mechanism to start said power means and said regulating means for each of said equal divisions of stepped movements, and means operated by said mechanism for rendering, said temperature sensitive means ineflective after initiating said mechanism and during each of said equal step division movement.

16. 'I'hecombination with a heating system, of regulating means including power means and a heat control member adapted to be moved back and forth by said power means between predetermined limits constituting a predetermined number of a series of equally divided stepped positions, a switch control mechanism for starting and stopping said power means for operating in either direction through one of said equally divided stepped positions of said predetermined limits, an electric circuit, a pair of opposed contacts in said circuit, means sensitive to temperature changes having movement to cooperate with said opposed contacts, camming means operated by said power means for moving to separate contact of either of said opposed contacts and said temperaturesensitive means during each of said equal divisions of movement, means for changing the effective movement of said camming means to vary-the extent of contact separation of said opposed contacts and said temperature sensitive means without changing said predeterminednumber of said equally stepped positions, said temperature sensitive means serving to initiate said mechanism to start said power means and said regulating means for each of said equal divisions of stepped movement.

, LUDWIG HOLLAND-m2, 

